1. Field of Invention
To save the earth, we need to use the unified approach for all the different circuit theoryies to invent the green circuit design theory. In other words, we need to have the multi-disciplinary approach of analog, digital, radio frequency (RF), power management unit (PMU) and power amplifier (PA) to work altogether to find new green technology with the unified approach. With the unified multi-disciplinary approach, we have made many fundamental breakthroughs in the green circuit design theory.
For the switch mode power supply, the switching loss is the biggest problem. In the switching of the huge output driver, the charging and discharging of the huge output driver waste a lot of energy. All the energy is discharged to the ground as the heat. Due to switch loss, the switching frequency cannot be high. However, the higher the switching frequency, the smaller the inductor and capacitor are. With the high switching frequency, the inductor and capacitor can be integrated on chip to save the energy further. Now, due to no green recycling mechanism, the switching loss is high. The switching loss high, then the switching frequency is low. For the low switching frequency, the inductor and capacitor are big. The big inductor and capacitor cannot be integrated on-chip. For the on-board inductor and capacitor, it needs energy to drive the large on-board inductor and capacitor. Therefore, the on-board large inductor and capacitor are not only waste material but also waste energy. The switch loss has a lot catastrophic disastrous effects.
With the green re-cycling mechanism, the switching loss is minimized that the switching frequency can be increased. With the high switching frequency, the size of the inductor and capacitor can be reduced to be integrated on-chip. With the on-chip inductor and capacitor, the energy is saved further.
For the power amplifier PA, all the cellular phones need the power amplifier. For the 3G, the PA uses 75% power of the cellular phone. However, the power efficiency is only 10%. Charging the battery take half hour and the cellular phone can use 2 days. However, for the 4G 4th Generation cellular phone, it uses the OFDM Orthogonal Frequency Division Multiplex modulation. For the OFDM, the PAR Peak Average Ratio is very large that the power dissipation is very large. There is no DC signal can be transmitted that the DC biasing is just waste. For the small signal in OFDM, the large DC biasing current is dissipated as heat.
For the 4G, the power efficiency is only about 1% and 99% of the energy is dissipated as heat. The battery size of 4G is about 8 times larger than the battery of 3G cellular phone. Charge for 2 hours and uses for 3 hours. It needs two batteries to swap between the battery charging and battery use.
For our invention, we make green energy means having the three innovations to solve the PA problem in 4G.    (1) we use the differential structure to have the voltage bias of zero DC current to get rid of the energy wasted by the DC current;    (2) We use the dynamic storage LC tank to store the reflected energy and the DC energy;    (3) Recycling the stored energy to be the transmitting energy again.With the green energy means, even for the 4G cellular phone, the power efficiency can be 75%. It can save many nuclear power plants in the U.S.
Conservation of the earth resource becomes a Green Movement. Not only recycling the material but also the energy needs to be recycled. Applying the energy-recycling concept in the circuit and chip design, it becomes the new styles of circuit and chip design, Green Circuit Design for Green Chip. The Green Circuit Designs for Green Chip includes many versatile fields, from the battery of electrical vehicle (EV), etc to RF Power Amplifier of cellular phone and plasma light, etc. We will apply the re-cycling energy concept in all the power-hungry design.
For the 3rd generation cellular phone, the battery can use for three days. However, for the 4th generation cellular phone, the battery is charged for two hours and used for three hours only. Comparing with the 3rd generation cellular phone, the size of the 4th generation cellular phone is about four times bigger and the battery is slide on the cellular phone. There are two batteries in one package. One battery is in use and the other battery is in charge. Therefore, we have to reduce the power of the portable cellular phone and personal computer for the coming age. The 75% of the power of wireless media is power amplifier. We need to increase the efficiency of the power amplifier.
For lighting, even bulb uses the Power Amplifier to light plasma bulb. The power amplifier has the low efficiency 30% only. It makes the energy loss tremendously. We have to develop the new circuit design style of the “switch inductor” and the “asynchronously event driven state machine” for the green circuit design of the green chip.
To increase the efficiency of the power amplifier, it needs the power management. To increase the efficiency of the power management, it needs to reduce the switching loss. To reduce the switching loss, it needs to recycle the energy. To recycle the energy, it needs the switch inductor.
The green circuit design is the switch inductor with the recycle of energy. The switch inductor is the conjugate concept of the switch capacitor. The switch capacitor has the sample & hold concept. The switch inductor has the switch & hold concept. The switch & hold of the switch inductor is the conjugate concept of the sample & hold concept of the switch capacitor.
With the switch inductor, the recycling circuit is much different from the resonant circuit. The resonant circuit doesn't have the switch. The energy is cycling in the resonant circuit with the natural frequency. The recycling circuit has the switch to control the flowing direction and the recycle of the energy.
The switching loss is PLoss=fCΔV where f is the switching frequency. The larger the frequency f is, the larger the power loss PLoss is. Before, the switching loss of the buck converter forbids the operating frequency to operate at high frequency. With the recycling energy, we can increase the switch frequency f without the increment of switch loss. Furthermore, with the increase of the switch frequency f, the device size L and C in the output driver of the buck regulator can be reduced that the L and C can be reduced and become the inductor-less and capacitor-free design.
The recycling energy of the switch inductor had better to work with the advanced control technology of the Adaptive Non-overlapping Crossing Zero Voltage Detector (VZ) and the Adaptive Zero Current Detector (IZ). With the VZ and IZ events, the event driven state machine can be developed to replace the clock driven state machine.
Furthermore, the new standard for the power management has set. The ripple of the power has set to be less than the 10 mV. It forces the power chip to use the multi-phase PWM. The multiphase power supplies still increase the switch loss. Now, with the re-cycling of the energy, the switch loss can be neglected and the output driver size is kept the same. Furthermore, increase the frequency, the driver size can be reduced. Therefore, the multi-frequency power supply is much better than the multi-phase power supply.
Both the PC and the wireless products have to solve the dynamic variance of the power management. The PC power management has the sudden requirement of current. The wireless power management has the sudden large variance of the voltage. To meet the sudden change of power requirement, the LDVR has to work with the switch mode power supply. At the normal operation, the switch mode power works to have the high efficiency. For the sudden variance of the current and/or voltage, the LDVR buffer will step in to boost up the voltage for the large crest factor of the large PAR (Peak to Average Ratio). Therefore, we need to have the unified approach to merge the Low Drop Voltage Regulator (LDVR) with the Switch Mode (SM) power supply.
The Scaling Power Management for Power Amplifier can increase both the efficiency of the power amplifier and the linearity of the power amplifier. The signal will see the same scaling power over input factor of (Vdd/Vi) that the gain of the power amplifier is linear over all the input Vi. It will increase the linearity of the power amplifier.
The Scaling Power Management is different from the envelope extraction of the power amplifier. The envelope extraction has the power level to be the exact shape of the waveform of the envelope. The Scaling Power Management doesn't need to have the exact shape of the input information. Furthermore, it keeps the safety margin that the output signal will not be truncated.
To increase the efficiency and the linearity of A type power amplifier, the adaptive-bias A type power amplifier is to have the bias of the operating point to vary according to the amplitude of the input voltage. To increase the efficiency further, the Conjugate-B-High-Linear-High Efficiency Power differential B type power amplifier is developed. The DC level of the input voltage is eliminated that the power efficiency can increase a lot.
Furthermore, the RF designers didn't have the new analytic methodology of the output power efficiency before. They fail to recognize the power amplifier problem. Now, with the multi-disciplinary of analog, digital, RF, power management and power amplifier, we invent the new analytic methodology of the output power efficiency and the new power managing amplifier (PMA) architecture. Now, with the green design, we have developed new style of power amplifier design to save the more than 80% energy.
2. Description of Prior Art
There is the dream of the green chip. However, nobody recognize the green chip problem is the green circuit. There is no systematic research work on the green circuit design. Since there is no fundamental research of the green circuit, the green chip concept is just a dream which cannot be implemented. In the past, the American car is a big car. The big car consumes a lot of fuel as consuming water does. Now, both the fuel and water become the scarce resource. We must have the conservation concept of both energy and resource. Before, the circuit design used the clock driven switch capacitor and the clock driven synchronous state machine design. The clock driven design has all the circuit to start to work at the clock edge and has the power surge. It generates a lot of power noise.
Before the power amplifier has the extremely low power efficiency being 10%. For the base station, the total energy efficiency is even lower to be 3%. Therefore, we need to increase the power efficiency for the power amplifier with the green circuit design of the green chip.
The modulation of the wireless standard has the low peak to average ratio (PAR) before. Now, for the 4th generation of the cellular phone and wireless standard, the peak to average ratio (PAR) is much higher. It pushes the operating point back off to the lower power efficiency operating range.
Furthermore, today power management is addressed to be the PC problem. The power management has the problem of latency. It cannot meet the requirement of the dynamic response of PAR of the wireless problem. Even the analog buck regulator cannot meet the fast transient of the load regulation, not to mention the digital buck regulator. Therefore, in our new approach, we have the unified approach to unify the fast LDVR with the normal operation SM together.
Today, the power amplifier has very low efficiency. To increase the efficiency, we need to work on the power management of the power amplifier. However, there is seldom considering both the power management and power amplifier at the same time. The power management cannot meet the transient behavior requirement of the power amplifier. However, there is no work address on the issue of the power management for the power amplifier. Today, the architecture of the power management has the fundamental problems. It never meets the tough requirement of the power amplifier. Therefore, the problem of the power management for the power amplifier is just left there. The power amplifier has the power efficiency to be 10% only.
The modern PMU design is load adaptive. It is not only designed for the voltage of power supply but also for the fast transient of the power supply. However, until recently the industry start to consider minimizing the ripple of the power supply. The power industry still doesn't consider the fast transient of the power supply. For the ripple of the power supply, the power manufacturer and venders just use the huge capacitor to walk around the fast transient of the power supply. However, for the wireless power amplifier, to increase the power efficiency, the supply power voltage needs to track the variance of the amplitude envelope of the input signal. The power supply needs to trace the amplitude envelope of the input signal in mega frequency range. It is far beyond the traditional PMU approach. Therefore, the traditional PMU just does not work in the green circuit technology. We need to make the innovation in the green PMU technology.